rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=485/1/0x4000000000000002 softirq=5781/5781 fqs=0 (detected by 1, t=10502 jiffies, g=5813, q=427) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4203 Comm: syz-executor338 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65 Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 RSP: 0018:ffffc90002e9f098 EFLAGS: 00000002 RAX: ffffffff81980400 RBX: ffff88807ac13bb0 RCX: 0000000000000000 RDX: 0000000000000038 RSI: 0000000000000000 RDI: ffffc90002e9f118 RBP: ffffc90002e9f1c0 R08: ffffc90002e9f117 R09: ffffc90002e9f0e0 R10: dffffc0000000000 R11: fffff520005d3e23 R12: ffffc90002e9f0e0 R13: 1ffff920005d3e18 R14: ffffc90002e9f140 R15: ffffc90002e9f300 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f127ec065bc CR3: 000000007448d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __perf_event_output kernel/events/core.c:7805 [inline] perf_event_output_forward+0x172/0x2e0 kernel/events/core.c:7832 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525 perf_swevent_overflow kernel/events/core.c:9601 [inline] perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 42 0b 9d 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc90002e9f720 EFLAGS: 00000206 RAX: 599e657c3beff200 RBX: 1ffff920005d3ee8 RCX: 599e657c3beff200 RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0 RBP: ffffc90002e9f7f0 R08: ffffffff901f10c7 R09: 1ffffffff203e218 R10: dffffc0000000000 R11: fffffbfff203e219 R12: ffffffff8c323400 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __unlock_page_memcg+0xea/0x100 mm/memcontrol.c:2093 zap_pte_range mm/memory.c:1384 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0xee4/0x2410 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x390 kernel/fork.c:1133 exit_mm+0x632/0x7b0 kernel/exit.c:557 do_exit+0x5b8/0x2110 kernel/exit.c:877 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f127eb895c5 Code: Unable to access opcode bytes at RIP 0x7f127eb8959b. RSP: 002b:00007fff3c97f878 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f127eb895c5 RDX: 00000000000000e7 RSI: ffffffffffffffd0 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f127ec3a120 R14: 00007f127ec3c4e8 R15: 00007f127ec3c500 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.435 msecs rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g5813 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=3616 rcu: rcu_preempt kthread starved for 10502 jiffies! g5813 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:27424 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4203 Comm: syz-executor338 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5365 [inline] RIP: 0010:lock_is_held_type+0x7c/0x190 kernel/locking/lockdep.c:5668 Code: 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c 8f 04 24 4c 8b 2c 24 fa 48 c7 c7 e0 39 2b 8a e8 4b 0e 00 00 65 ff 05 74 41 41 76 <83> bb e8 0a 00 00 00 7e 4b 44 89 fd 49 89 df 49 81 c7 f0 0a 00 00 RSP: 0018:ffffc90002e9ef30 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff8880291d9dc0 RCX: 599e657c3beff200 RDX: 0000000000000000 RSI: ffffffff8a2b39e0 RDI: ffffffff8a7a48c0 RBP: 00000000ffffffff R08: ffffc90002e9f117 R09: ffffc90002e9f0e0 R10: dffffc0000000000 R11: fffff520005d3e23 R12: dffffc0000000000 R13: 0000000000000046 R14: ffffffff8c31ef60 R15: 00000000ffffffff FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f127ec065bc CR3: 000000007448d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: perf_get_guest_cbs include/linux/perf_event.h:1274 [inline] perf_misc_flags+0x56/0x1b0 arch/x86/events/core.c:2961 perf_prepare_sample+0x132/0x1cb0 kernel/events/core.c:7632 __perf_event_output kernel/events/core.c:7812 [inline] perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7832 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525 perf_swevent_overflow kernel/events/core.c:9601 [inline] perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 42 0b 9d 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc90002e9f720 EFLAGS: 00000206 RAX: 599e657c3beff200 RBX: 1ffff920005d3ee8 RCX: 599e657c3beff200 RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0 RBP: ffffc90002e9f7f0 R08: ffffffff901f10c7 R09: 1ffffffff203e218 R10: dffffc0000000000 R11: fffffbfff203e219 R12: ffffffff8c323400 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __unlock_page_memcg+0xea/0x100 mm/memcontrol.c:2093 zap_pte_range mm/memory.c:1384 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0xee4/0x2410 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x390 kernel/fork.c:1133 exit_mm+0x632/0x7b0 kernel/exit.c:557 do_exit+0x5b8/0x2110 kernel/exit.c:877 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f127eb895c5 Code: Unable to access opcode bytes at RIP 0x7f127eb8959b. RSP: 002b:00007fff3c97f878 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f127eb895c5 RDX: 00000000000000e7 RSI: ffffffffffffffd0 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f127ec3a120 R14: 00007f127ec3c4e8 R15: 00007f127ec3c500